The conventional fitness ball is in an annular shape, and it usually has protruding beads spread on the surface, which offers a massage effect on human body. However, this conventional fitness ball is annular, which rolls easily. Therefore, it is not stable when a human body is leaning against it. Once the human body is out of balance, it would fall out of the fitness ball. This has a negative impact for the beginner or a user with poor balance. Also, for some users, this fitness ball is not a proper fitness tool. Therefore, the industry has developed other non-annular fitness balls, such as semi-annular or semi-columnar fitness ball, which do not have the rolling function because of the removal of the annular design. Though the stability and safety are improved when in use, it has a rocking effect only, which decreases the practicability.
Thus, to overcome the aforementioned problems of the prior art, it would be an advancement in the art to provide an improved structure that can significantly improve the efficacy.
To this end, the inventor has provided the present invention of practicability after deliberate design and evaluation based on years of experience in the production, development and design of related products.